The inventions described herein relate to catheters and other devices adapted for insertion into lumens in the body, and in particular to those catheters for which proper operation requires confirmed contact between the catheter and a body lumen.
The catheter placement system and operator interface described below are intended to facilitate placement of catheters into body lumens. We have developed a catheter for treating the ovarian pathway of women. This catheter is described in U.S. Pat. No. 6,309,384, and provides two pairs of bipolar ring electrodes on the distal tip of a catheter, and an occlusive mass within the distal tip. The catheter is used to occlude ovarian pathway by inserting the distal tip into the ostium, seating the distal tip firmly within the ovarian pathway, applying RF energy to the ovarian pathway through the electrodes to injure a segment of the ovarian pathway, and then ejecting the occlusive mass into the ovarian pathway (in the injured segment). The procedure is highly effective. The ease of use of the system can be enhanced, and the certainty of property placement can be more easily determined, with our new placement detection system and operator interface. Additionally, several procedural safeguards can be implemented through the interface.
The methods and devices described below provide for more certain operation of catheters, such as our ovarian pathway treatment catheters, into lumens of the body. The catheter itself is fitted with a circumferential array of electrodes, which, when placed in a circuit for which impedance or resistance is monitored, have varying effect on the measured impedance or resistance depending one whether the electrodes are in contact with the luminal tissue of the ovarian pathway or not. The impedance or resistance also varies, in a predictable manner, with the degree of contact between the electrodes and the luminal tissue of the ovarian pathway. An operator interface is provided which communicates the impedance measurement information to the operator in an intuitive display, and permits the operator to control the catheter. Additionally, a control system is provided which controls the catheter to prevent certain undesired modes of operation, and to control operation of the catheter in the event of an interruption in proper operation. Finally, an RF circuit which is specially adapted to supply the necessary RF signals and measure the impedance or resistance of tissue in contact with the electrodes, given that the circuit includes otherwise overwhelming capacitive impedance inherent in the structure of the catheter (which is several feet long, and includes the many wires necessary to supply and sense the electrodes running in close proximity in the necessarily slender catheter).